Aerofoil



E. P. GAINES Aug. 30, 1932.

AEROFOIL Filed Aug. 28. 1929 2 Sheets-Sheet l INVENTOR BY v ATTORNEY E. P. GAINES Aug. 30, 1932.

AEROFOIL Filed Aug. 28, 1929 2 Sheets-Sheet 2 S INVEN'EQR ATTORNEY it is translated or Patented Aug. 30,

UNITED STATES PAT ED'IURD P. GADTIS, OI 'OOLUIIBIA, sour: CAROLINA v moron Application fled Aunut 88, 1988. Serial 10. 888324.

My invention relates to aircraft and more particularly to aerofoils.

It is already known that when an aerofoil inclined at an angle to the air thru which which acts against it, that the lift coeflicient of such aerofoil increases with the increase of its angle of attack u to a certain critical angle which past experiments indicate varies between 12 and 20. After this critical angle is passed the value of the lift coefiicient of the aerofoil decreases owing to a discontinuity of the air flow over the upper surface of the aerofoil, which disturbed air flow, i. e., eddyin air or vortices, is known as burbling. W en burbling begins the air ceases to exert its full suction efiort and the lift coefficient rapidly falls off. Experiments further show that burbling occurs first in the vicinity of the center '0 the aerofoil and continues outwardly progressively toward the tips.

'lo preventburbling it has heretofore been proposed to provide aerofoils with a leading edge portion and with a main portion adapted to be set with respect to each leave a longitudinally extending open slot thru the aerofoil. It has also been proposed to provide in the upper surface of an aerofoil slots or openings thru which air is adapted to escape, the escaping air being directed rearwardly to sweep away the dead air. caused by the forward movement of the aerofoil thru space. In neither of said previously suggested schemes, however, is any provision made for controlling the volume of air escaping over the top surface of the aerofoil, nor is any provision made for directing a greater volume of air over the center or inner end portion thereof than over its outer end or ends. Moreover, with the object in view of retarding burbling, no one has suggested an arrangement whereby the air is taken in thru a control inlet, directed laterally thru air passages formed interiorly of the aerofoil, and liberated onto the upper surface thereof as well as onto the upper surface of a hinged flap or aileron fastened to or adjacent to the trailing ed s of the wing. Nor has any one propose l ejecting air over the upper surface of the aerofoil other to ENT, OFFICE from slots in air passages transverse to the line of flight, in taneousl combination with a simuloperated flap or aileron fastened to or a jacent to the trailing edge of the wing.

According to the present invention there is provided in the more interior air aerofoil or aerofoils one or passages thru which the an escaping therefrom onto the top surface of the aerofoil or aerofoil taper outwardly or have ing slots or outlets (or bot volume of air may be dire surface of the is directed. Where a taper wing is provided the air passages either open thereto taperh) so that a greater cted onto the upper aerofoil nearer to its inner end or mid-section than to its outer end or tips. foils are provide ailerons are used passages and slots,

uniform cross section and the slots of "uniform width. With each said there is associated an controlled air scoop,

air passage appropriate manually for regulating the vol-.

ume of air admitted to said air passages. One of the air passage outlets is located nearer to the leadin edge of the aerofoil than to its trailing of said the traillng edge e ge, whereas the other passages has its outlet so related to flap or aileron as to admit of an air discharge over its upper surface.

Preferably the an trailing edge flaps scoop or scoops and the or allerons are so interconnected as to provide for their simultaneous operation; the scoop or scoops being opened to admit air to the air passages simultaneously with the movement of the'trailing edge flaps or ailerons. incidentally,

in their normal clude the escape of air from th The flaps or ailerons position, pree trailing edge or rearwardly located" slot. It is only when said flaps or ailerons are biased downwarddischarge over the ly that need for an air upper surface occurs. and directed not only Air thus controlled eliminates burbling over the aerofoil surfaces as higher angles of but it accomplishes cturally simple and nner subject at all attack than heretofore,

the desired end in a str'u entirely satisfactory ma times to perfect manual control.

To force Fig. 1 is a front view of a low wing monoplane having ta ered wings;

Fig. 2 is a iagrammatic view showing the wing construction and its relation to the fuselage or machine, and

Fig. 3 is a cross-section of the wing adjacent to the fuselage showing certain details of construction.

As intimated, the invention is shown as embodied in a low taper wing monoplane in which the fuselage is designated as 1 and the opposed wings as 2. Air scoops 1 and 2 are built into the bottom of the fuselage 1' in a manner such that their leading edges may be lowered to divert the slipstream into transverse air passages 3 and 4 which extend lengthwise the win s or aerofoils 2. Air passa e 3, as herein s own, is the space between t e front win beam 3' and the leading edge of the aero oil. It is formed by lacing the usual metal or wood nose covermg inside the nose ribs (not shown). Air passage 4 is a box-like structure located beind the rear beam 4 of the wing and is attached inside the wing ribs (not shown).

Preferably the box-like structure is braced interiorly by means of small diagonal streamline struts whose major axes are arallel to the wing beams. The rear wall 0 the box-like structure is provided with an ob- "long slot or slots thru which the air escapes to an airgap or outlet 6 provided at the trailing edge of the mam portion of the wing. For reasons hereinafter pointed out, the air passages 3 and 4 taper or decrease in crosssectional area from the inner to the outer end of the wing, the taper idea being also carried out in the formation of the wing slots or air outlets thru which the air in circulation is liberated onto the upper surface of either the wing proper or wing flap or aileron with which the wing is equipped. The wing flap as herein shown is designated as 9 and the aileron mounted at the outer end of the wing, is up position, the win flap 9 closes the air slot 6 whereas in its down position said slot is uncovered to provide for the esca e of air. That which is'true of the wing ap 9 in this respect is true also of the aileron 10.

designated as 10 In its- A shutter 7 for the forward or leading edge slot is normally held closed by the spring hinge 8 that the continuity of the aerofoil section may be maintained at low angles of attack. a

The operation of the arrangement is as follows: Consider the aerofoils or wings set for normal cruising o eration as shown by the dotted ortions of Fig. 3, i. e. with shutter 7 close wing flap 9 up, an in neutral position. The pilot in his seat 19 moves the lever 11 shown in Fig. 2 to the forward notch of the quadrant 12. Thus moved, rod 13 pushes arm 14 forward to open the air scoop 1. At the same time, rod 15 pulls arm 16 forward to open the air scoop 2. Also, torq aileron 10 ue tube 17 rotates counterclockwise pullmg wing flap 9 down by means of the rod 18. With the parts thus ositioned, air is caught from beneath the uselage by scoops 1 and 2 and is deflected into the transverse air passages 3 and 4 by suitable partitions placed transversely of the fuselage at the rear extremity of the air scoops. Shutter 7 is opened by a combination of the air pressure from within and the suction occurring over the upper surface of aerofoil. (Shutter 7 can be hinged at its rear edge and may be opened downward and inward b mechanical means if desired or, if preferre it may be entirely omitted.) Air gap 6 is opened by the lowering of the wing ap 9. The air is propelled thru the air passages 3 and 4 and out thru the slots 5 and 6 by the combination of forces of atmospheric pressure plus slipstream and propeller blast as well as by the partial vacuum existing over the upper surfaces of the aerofoil. If desired, by sweeping the wings back, the flow of air in the air passages can be accentuated.

The system as herein shown is semi-automatic as the resultant air forces acting on the air scoops 1 and 2 tend to balance those forces acting on the wing flap 9. Accordingly, but little force is required to operate the control device or lever 11.

Prevention of ice forming on the wings is accomplished by diverting the heated air from the power plant (not shown) into the air scoops 1 and 2 and thence thru the air passages 3 and 4 from which it escapes.

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art after understanding my invention that various changes and modi cations may be made therein without departing from the s )irit or scope thereof. I aim in the appended claims to cover all such modifications and changes.

What I claim is:

1. In aircraft, a fuselage; an aerofoil provided with an interior air passage transverse to the direction of flight and thru which air passes outward within said aerofoil, having an outlet opening thru which the air within v 1 I j I, said passage is adapted to escape, and havin flap normally closing one said outlet opening, an inlet opening positioned a jacent to sai separate closures for said inlet openings and fuselage, and a movable trailing edge flap adapted, by its movement, to control said air escape.

2. In aircraft, a fuselage; an aerofoil provided with an interior air passage transverse to the direction of flight and thru which air passes outward within said aerofoil, having a trailing edge outlet opening thru which the air within said passage is ada ted to escape, and having an inlet opening or said interior air passage positioned adjacent to said fuselage, and a movable trailing edge flap adapted, by its movement to cover and uncover said opening. 7

3. In aircraft, a fuselage; an aerofoil provided with an interior air passage transverse to the direction of flight and thru which air passes outward within said aerofoil, having an outlet openin thru which the air within said passage is a apted to esca e, and having an inlet opening positioned a jacent to said fuselage through which air passes into said interior air passage, and a trailing edge flap mounted in such relation to said outlet opening as to admit of the air escape directly onto its upper surface.

4. In aircraft, a fuselage; an aerofoil provided with an interior air passage transverse to the direction of flight and thru which air passes outward within said aerofoil, having an outlet opening thru whichthe air within said passage is adapted to escape, and having an inlet opening adjacent to said fuselage through which air is adapted to enter said passage, and a trailing edge flap mounted in such relation to said outlet opening as to admit of the air escape directly onto theupper surface of the trailing edge flap at a paint rearwardly removed from its leading e e.

In aircraft, an aerofoil provided with an air passage having an inlet opening and an outlet opening, a closure for said inlet opening, and a closure for said outlet opening operable automatically under the influence of the varying air forces produced by the opening and closing of said inlet opening.

6. In aircraft, an aerofoil provided with an interior air passage transverse to the direction of flight and having an inlet opening and an outlet opening in the upper exterior surface of said aerofoil, a closure for said inlet opening, a wing flap movable to cover and uncover said outlet opening, said wing flap being so related to said outlet opening so as to admit of an air discharge over the upper surface thereof when said outlet opening is uncovered, and a mechanical connection between said closure and said wing flap for 00- ordinating the movements thereof.

7. In aircraft, an aerofoil provided with separate interior air passages each having an inlet opening and an outlet opening, a wing separate interior air inlet opening and an outlet opening, a wing for operating both means operable to move said wing flap to uncover one said outlet opening simultaneously with the opening movement of said inlet closures.

8. In aircraft, an aerofoil provided with passages each having an flap carried by and movable relatively to said aerofoil, one said outlet opening being adapted to discharge air over the uppersurface of said aerofoil nearer to its leading edge than to its trailing ed e, and the other said outlet opening being adapted to discharge air over the upper surface of said wing flap, separate closures for said inlet openings, and means said closures simultaneously with the movement of said wing flap.

9. In aircraft, an aerofoil provided with separate interior air passages transverse to the direction of flight each having an inlet opening and an outlet opening, separate closures for said inlet opening, an air scoop positioned adjacent to the inner end of said aerofoil for causing air to flow in said inlet opening, a control device, and a connection extending between said control device and each said closure for operating all of said closures simultaneously.

10. In aircraft, an aerofoil provided with separate interior air passages each having an inlet opening and an outlet opening, separate closures for said inlet openings, a wing flap, a control device, and a connection between said control device and each said closure and said wing flap for moving said wing flap and operating all of said closures simultaneously.

11. In aircraft, an aerofoil consisting of a main section containing an air passage substantially transverse to the direction of flight, having formed therein an outlet slot and having an inlet opening formed adjacent to the inner end of said section; a wing flap associated with said main section; and common means to lower the wing flap and at the same time cause air to flow into saidinlet opening, through said air passage along the span of said aerofoil and out through said outlet s ot.

12. In aircraft, an aerofoil provided with an interior air passage transverse to the di rection of flight and having an inlet opening and an outlet opening in the upper exterior surface of said aerofoil, a closure for said inlet opening adapted, when open, to direct outside air through said inlet opening, a flap closure for said outlet opening, and means for operating both said closures simultaneously.

13. In aircraft, an aerofoil provided with an interior air passage transverse to the direction of flight and having an inlet opening and an outlet opening in the upper exterior surface of said aerofoil, a closure for said inlet opening ada ted, when open, to direct outside air throug said inlet opening, a wing flap normally closing said outlet opening, and means for movng said wing flap to uncover said outlet opening simultaneously with the opening of said inlet opening.

14. In aircraft, an aerofoil provided with an interior air passage transverse to the di- 1o rection of flight and through which air passes outwardly within said aerofoil and having an outlet opening through which the air within said passage is adapted to esca e and having an inlet opening positioned a jacent the inner end of said aerofoil, and a trailing edge flap mounted in such relation to said outlet opening as to admit of the air escape di- 7 rectly onto its upper surface.

In testimony whereof I hereunto afiix my signature.

EDMUND P. GAINES. 

